Elastic yarn holding means for circular knitting machines



Apnl 23, 1968 .J. QFARMER 3,379,036

ELASTIC YARN HOLDING MEANS FOR CIRCULAR KNITTING MACHINES Filed July 13, 1965 4 Sheets-Sheet 1 April 23, 1968 J o. FARMER I 3,379,036

ELASTIC YARN ROLDING MEANS FOR CIRCULAR KNITTING MACHINES Filed July 13, 1965 Sheets-Sheet 2 l; igi \zzg z.

April 23, 1968 J. o. FARMER ELASTIC YARN HOLDING MEANS FOR CIRCULAR KNITTING MACHINES 4 Sheets-Sheet 5 Filed July 15, 1965 April 23, 1968 J. o. FARMER ELASTIC YARN HOLDING MEANS FOR CIRCULAR KNITTING MACHINES Filed July 13, 1965 4 Sheets-Sheet 4 United States Patent 3,379,036 ELASTIC YARN HGLDING MEANS FOR CIRCULAR KNITTING MACHINES James Otis Farmer, Garfield Park, New Castle, Del., as-

signor to E. I. du Pont de Nemours and Company, Wilmington, DeL, a corporation of Delaware Filed July 13, 1965, Ser. No. 471,526 3 Claims. (Cl. 66-145) ABSTRACT OF THE DISCLOSURE A holding device on a circular knitting machine for clamping yarn from an inactive elastic yarn feed finger and located on a line between the feed finger and a yarnsevering means, the device comprising a tube containing a notched rod extensible between a yarn engaging position exterior of the tube and a yarn holding position within the tube mounted vertically above and cooperating with a recess in the dial of the knitting machine, and means for actuating said rod in accordance with the deactivation of the feed finger to clamp the yarn before severing thereof.

This invention relates to yarn-holding devices and particularly to devices for holding yarn in a knitting machine.

In present-day circular knitting practice, it is common to employ a plurality of yarns for a given feeding station on the machine, the yarns being introduced to and removed from the knitting operation selectively according to a predetermined sequence to provide the desired pattern in the knitted fabric. A plurality of yarn feed fingers or other means are provided to bring the various yarns into knitting position and to remove them from knitting position as required. When a given yarn is removed from the knitting position, it is severed and the free end is retained by a holding device of some kind so that the yarn will be available for subsequent re-introduction to the needles as required.

Many kinds of holding devices have been employed in the past, including simple spring clamps and more complicated air-actuated devices. While these holding means have been generally satisfactory for inelastic yarns, difliculties have frequently been encountered in knitting elastic yarns because the retractive forces of such yarns cause them to withdraw from the restraining action of the holding clamp or similar device.

The present invention is, therefore, directed to a simple, effective, and positive means for holding elastic yarns when they are out of service in a knitting operation. It will be understood, of course, that the device is equally effective in holding inelastic yarns.

The holding device of this invention comprises: a tubular body having an opening at one end, a rod slidably positioned in the tubular body, means operatively connected to said rod to, firstly, advance said rod from a retracted position within said tubular body to an extended position in which a portion of said rod projects from said tubular body opening and, secondly, to return said rod from said extended position to said retracted position, said rod having a filament-receiving notch at a location which is exterior of said tubular body when said rod is in said extended position but which is interior of said tubular body when said rod is in said retracted position.

The invention will be more fully understood by reference to the explanation hereinafter taken together with the accompanying drawings wherein:

FIGURES 1a and lb are side and front views, respectively, of the holding device of this invention when the rod is in the extended position;

FIGURES 2a and 2b are corresponding views when the rod is in the retracted position;

FIGURE 3 is a schematic plan view of parts of a knitting machine showing a yarn in the knitting position;

FIGURE 4 is a similar view when the same yarn is in the hold position; and

FIGURES 5 and 6 represent schematically two different means for actuating the holding device of this invention.

With respect to the drawings, it will be understood that only those parts of the knitting machine are shown that are necessary to an understanding of the invention. Because the invention may be employed on a number of different kinds of knitting equipment, the exact parts and locations will vary from machine to machine. The various parts illustrated are not necessarily shown in exact scale or in exact spatial relationship to each other, but all are conventional parts of knitting machines well understood by those skilled in the knitting art.

Referring now to FIGURES la, 1b, 2a and 2b, the holding device 50' of this invention is shown mounted in place over the dial cap 41 of a circular knitting machine. The holding device 50 is fixedly mounted in position above the dial cap by any suitable means, not shown, to any convenient part of the knitting machine. The holding device 50 consists of tube 51 having opening 56 at one end and rod 52 which is retractably and extensively mounted in the tube 51. The rod 52. is notched near its lower extremity as indicated at 53 so that the notched portion of the rod 52 projects from opening 56 when the rod 52 is in the extended position but is within tube 51 when the rod is in the retracted position. The tube may be bevelled as indicated at 54. Recess 42 is provided in dial cap 41 and the holding device 50 is so positioned that rod 52, when in the extended position, will seat in recess 42. Recess 42 is of slightly greater diameter than the diameter of rod 52 and the depth of the recess 42 is such that, when rod 52 is extended and seated in recess 52, the lower lip of notch 53 in rod 52 will be flush with the top of dial cap 41.

In FIGURES 1a and 1b, yarn 11 has just been removed from the knitting position. The continued operation of the knitting machine has brought yarn 11 past the hold ing device 50 in such a way as to pass into notch 53 in extended rod 52. Shortly thereafter in the cycle of operations, as shown in FIGURES 2a and 2b, rod 52 is caused to retract within the body of tube 51, causing yarn 11 to be firmly held between rod 52 and the inside walls of the tube 51. Immediately thereafter, the leading end of yarn 11 is severed and, in the case of an elastic yarn, retracts to form the short end shown in FIGURE 2b, while the remainder of yarn 11 is then held in readiness for re-introduction to the knitting needles.

The sequence of operations is more clearly indicated in FIGURES 3 and 4. In FIGURE 3, yarn 11 is shown passing through conventional yarn feed finger 12 to the needles at feeding station 13. In this drawing, yarn 11 is in the knitting position. The holding device 50 is shown mounted in place over dial cap 41 in a position between the feeding station indicated generally at 13 and the severing blade 15. All parts mentioned except the holding device 50 of this invention are conventional parts of a knitting machine, are employed in their normal mannor of operation, and hence are not illustrated in detail.

When the predetermined sequence of operations calls for yarn 11 to be removed from the knitting position, yarn feed finger 12 lifts yarn 11 from the needles in the known manner. Since yarn 11 is at this stage bound into the knit structure, the continued operation of the knitting machine causes yarn 11 to be drawn across dial cap 41, past the holding device 50 in a manner corresponding to FIGURES 1a and 1b. Shortly before yarn 11 reaches the severing device 15, the holding device 50 is actuated to raise rod 52 within tube 51, thus firmly clamping yarn 11. The continued operation of the knitting machine thereafter causes the leading end of yarn 11 to be severed from the knit fabric structure, whereupon, in the case of an elastic yarn, the now-free end retracts to form the short end shown in FIGURES 2a, 2b and 4, while the remainder of yarn 11 continues firmly held between yarn feed finger 12 and the holding device 50 and is thus readily available for reintroduction at the knitting station 13 when required.

When yarn 11 is re-introduced to knitting at feed station 13 by feed finger 12, knitting is allowed to proceed for 8 or needles, whereupon rod 52 is caused to extend from tube 51 and release yarn 11. This general sequence of operations will be readily understood by those skilled in the knitting art.

FIGURES 3 and 4 show in phantom a conventional spring binder 14 in its usual position. This binder need not be removed from the knitting machine when the holding device 50 of this invention is employed, but binder 14 should be held in the inoperative position when holding device 50 is in operation.

The exact dimensions of the various parts of the holding device 50 of this invention are not critical, except that rod 52 should fit snugly, although not tightly, within tube 51. Rod 52 should slide freely within tube 51 but with suificiently close tolerance that yarn 11 is firmly clamped between rod 52 and the inside walls of tube 51 when the rod 52 is in the retracted position shown in FIGURES 2a and 2b. The dimensions of notch 53 in rod 52, with respect to both depth and height, are not critical, it being necessary only that the notch be of such dimensions relative to the yarn that the yarn is easily led into the notch. Likewise, the dimensions of bevel 54, if present, are not critical. Bevel 54 is provided simply as a guide surface to assist in insuring that yarn 11 will be led into notch 53 in rod 52 as yarn 11 is drawn past the holding device 50 in the course of operation of the knitting machine. Similarly, the height at which holding device 50 is mounted over dial cap 41 is not critical. It is necessary only that there be sufficient space between the bottom of tube 51 and the dial cap 41 to permit easy access of yarn 11 to the notch 53 in rod 52 when the rod 52 is in the extended position. As indicated in FIGURES 3 and 4, the holding device 50 is positioned over dial cap 41 so as to be in line between yarn feed finger 12 and severing device 15.

Any suitable materials of construction may be used for the holding device 50. Examples of suitable materials are ordinary cold rolled steel, stainless steel, machined aluminum, or molded plastics, such as nylon.

By way of example, a yarn holder 50 is fabricated from type 316 stainless steel, with the following dimensions:

Tube 51:

Outside length-2.513 in. (63.830 mm.). Outside diameter-0.375 in. (9.525 mm.). Inside length-2.015 in. (51.181 mm.). Inside diameter-0.1285 in. (3.264 mm.). Wall thickness-0.125 in. (3.175 mm.).

Bevel 54 at angle of to vertical wall is filed to 0.020 in. (0.508 mm.) from opening 56 in bottom of the tube 51.

Rod 52:

Lcngth2.000 in. (50.800 mm.). Diameter-0.125 in. (3.175 mm.). Notch 53:

Bottom of rod to lower edge of notch-0.109 in.

(2.769 mm.). Height of notch0.062 in. (1.575 mm.). Maximum depth of notch-0.265 in. (6.731 mm.).

This device, equipped with the slot 55, lug 81, and biasing spring 58 shown in FIGURE 6, is mounted on a Scott 8: Williams All Multi Feed" model circular knitting machine in the location generally indicated in FIG- URES 3 and 4, and is actuated by the mechanism shown in FIGURE 6 and described in greater detail hereinafter. Recess 42 with a diameter of 0.250 in. (6.350 mm.) and a depth of 0.109 in. 2.769 mm.) is drilled in dial cap 41. The holding device is mounted over recess 42 so that rod 52, when in the extended position, seats in recess 42 with the lower edge of notch 53 flush with the surface of dial cap 41. When so mounted, there is a clearance of 0.045 in. (1.143 mm.) between the bottom of tube 51 and the surface of dial cap 41. This device is found to provide completely positive and effective holding action when employed with a variety of elastic yarns representative of those in wide commercial use, such as spandex yarns over a range from 10 to 140 denier. Those skilled in the art will recognize that some modification of specific dimensions may be required, without departing from the inventive concept, to accommodate yarns of other sizes.

The rod 52 and the opening 56 in tube 51 are illustrated herein as having a round cross-section. This configuration is, of course, simple and convenient to manufacture. It will be understood, however, that other crosssections can be employed without departing from the spirit of the invention. Thus, both the rod 52 and the opening 56 in tube 51 may be, for example, square, hexagonal, octagonal, or elliptical, or the rod 52 and the opening 56 in tube 51 may be of different cross-sections so long as the fit is sufficiently snug to provide firm gripping action on yarn 11 between rod 52 and the inside walls of tube 51 when rod 52 is in the retracted position. The external cross-section of tube 51 is, of course, immaterial.

The exact mechanical means employed to activate the holding device of this invention as required in the course of the knitting cycle is not a part of this invention. It will be apparent that operation of holding device 50 must be timed in conjunction with other operations of the machine, hence, will be suitably controlled by appropriate means from the main pattern drum or other sequence-regulating device, as can be readily devised by the skilled mechanic to suit a given knitting machine. FIGURES 5 and 6 show for purposes of illustration two arrangements that can be used, but many others are possible.

In FIGURE 5, the wall of tube 51 is provided with a slot to permit reciprocal vertical movement of arm 61 fastened to rod 52. Spring 63 is fastened to arm 61 at 65, and is similarly fastened at 64 to bracket 62 provided on top of tube 51. It will be apparent that the action of spring 63 is to bias rod 52 to the retracted position. Extension of rod 52 can then be accomplished by coaction of lever 71 with arm 61. Lever 71 is pivoted at 72 and is journaled at 73 to push rod 74. Push rod 74 in turn is actuated in a conventional manner by a cam drum on the knitting machine in a fashion similar to the operation of the yarn feed fingers as will be well understood by skilled knitting mechanics. As already indicated, when lever 71 is returned to its rest position, spring 63 causes rod 52 to return to its retracted position.

In the alternate arrangement of FIGURE 6, tube 51 is again provided with slot 55 to permit reciprocal vertical movement of lug 81 fastened to rod 52. Spring 53, contained in tube 51, biases rod 52 to the extended position. Retraction of rod 52 is accomplished by using a part of the yarn feed finger mechanism already provided on the knitting machine. When rod 52 is to be retracted, push rod 94, operated conventionally from the cam drum of the knitting machine, rises to contact lever 92 pivoted at 93. Lever 92 is connected to yarn feed finger in conventional manner by wire 88, fastened as indicated at 91 and 87. Yarn feed finger 85 is pivoted at 86 and flexible cable 83 is attached to yarn feed finger 85 at 84 and to arm 81, attached to rod 52, at 82. Because of the pivoting actions at 86 and 93, it will be apparent that upward movement of push rod 94 will cause yarn feed finger 85 to pull downward on flexible cable 83 to cause retracting movement of rod 52 into tube 51 against the biasing action of spring 58. For convenience, flexible cable 83 5 may be clamped in position by bracket 89 mounted on tube 51.

It will, therefore, be apparent that this invention provides a yarn holding device for knitting machines that is extremely simple and uncomplicated in both construction and operation, yet provides a completely effective holding action. It will be noted that yarn held by the device is doubly held, since it is gripped between the rod 52 and the inside Walls of tube 51 both as it enters the tube and as it leaves the tube. This positive holding action is particularly desirable for elastic yarns, which have heretofore tended to escape the holding action of the conventionally used binders. The holding device of this invention is, moreover, readily adaptable to any of a number of various kinds of knitting equipment, does not require a high order of precision in its manufacture, is durable in itself, and does not provide undue wear on the yarn with which it is used, because of the simplicity of its construction and operation.

It will be understood that the embodiments shown are for purposes of illustration only and that modifications may be made within the spirit of the invention, which is, therefore, intended to be limited only as defined by the appended claims.

What is claimed is:

1. In a circular knitting machine including a yarn feed finger (12), a dial cap (41), a feeding station (13) located at the periphery of the dial cap (41), a yarn severing blade (15) located at the periphery of the dial cap (41) at a point remote from the feeding station (13) whereby, when the yarn feed finger (12) withdraws a yarn from the feeding station (13), continued operation of the machine wil cause the yarn to be drawn across the blade (15) and severed, the improvement wherein a yarn holding device (50) is mounted vertically above the dial cap (41) in line between the yarn feed finger (12) and the severing balde (15), the holding device (50) comprising a tubular body (51) having constant interior transverse dimensions throughout its length and having an opening (56) at its lower end, a rod (52) slidably positioned within the tubular body (51) and having transverse dimensions slightly smaller than the corresponding interior dimensions of the tubular body (51) whereby the rod (52) fits snugly but not tightly within the tubular body (51), means operatively connected to the rod (52) to, firstly, advance the rod (52) from a retracted position within the tubular body (51) to an extended positioned in which a portion of the rod (52) projects from the opening (56) in the tubular body (51) and seats in a recess (42) in the dial cap (41) and, secondly, to return the rod (52) from the extended position to the retracted position, the rod (52) having a yarn-receiving notch (53) near its lower extremity so that the notch (53) is exterior of the tubular body (51) when the rod (52) is in the extended position but is interior of the tubular body (51) when the rod (52) is in the retracted position, the depth of the recess (42) in the dial cap (41) being such that, when the rod (52) is in the extended position and seated in the recess (42), the lower lip of the notch (53) in the rod (52) is flush with the top of the dial cap (41).

2. The apparatus combination defined in claim 1 wherein the tubular body (51) has a vertical slot (55) in its wall and wherein the means for advancing and returning the rod (52) comprises an arm (61) on the rod (52) and extending through the slot (55), a helical spring (63) connecting the arm (61) to the tubular body (51) and tending to retain the rod (52) in a retracted position Within the tubular body (51) and means operatively connected to the arm (61) to advance the rod (52) from the retracted position to the extended position.

3. The apparatus combination defined in claim 1 Wherein the tubular body (51) has a vertical slot (55) in its wall and a closure at its upper end, and wherein the means for advancing and retracting the rod (52) comprises an arm (81) on the rod (52) and extending through the slot (55), a helical spring (58) abutting the head of the rod (52) and the closure of the tubular body (51) and tending to urge the rod (52) to the extended position and means operatively connected to the arm (81) to return the rod (52) from the extended position to the retracted position.

References Cited UNITED STATES PATENTS 2,337,781 12/1943 Fregealle 66-134 2,377,729 6/1945 Toone et al. 66-134 2,388,750 11/1945 Lawson et al 66-134 X 2,432,110 12/1947 Lambach 66-145 2,569,822 10/ 1951 Miller 43-4495 2,719,381 10/1955 Matras 43-4495 2,867,936 1/1959 Lambach 43-4495 FOREIGN PATENTS 742,536 12/ 1955 Great Britain.

ROBERT R. MACKEY, Primary Examiner. 

